Vibratory motor for dry shavers and the like



I. JEPSON Oct. 27, 1942.

VIBRATORY MOTOR FOR DRY SHAVER AND THE LIKE Filed March 18, 1940 3 Sheets-Sheet 1 a a 4 6 A, H Z a M W 3 J W M v 33 1 A0 7W I I T a J MM; 2 U M V. w m J M lw W 9 f 7 M a 1 y 5 8 x 6 T 4 a n M Z w 9 2 a F 1 O I g .6 o

x in I "w J 2 I 2 m9 n a 7 a TQ. .1 u u a lb f "m o A w L nn o I llflw I r o .0, ..H, I y a 1 a 9 m 7 4 J m H z I. JEPSON Oct. 27, 1942.

VIBRATORY MOTOR FOR DRY SHAVER AND THE LIKE Filed March 18, 1940 3 Sheets-Sheet 2 Oct. 21, 1942. l. JEPSON VIBRATORY MOTOR FOR DRY SHAVER AND THE LIKE Filed llarcti 18, 1940 3 Sheets-Sheet 3 NW w" llllllllllll Patented Oct. 27, 1942 2,299,952 VIBRATORY MOTOR FOB DRY SHAVERS AND THE LIKE Ivar Jepson,

poration of Illinois Chicago, 111., assignor to Chicago Flexible Shaft Company, Chicago,

111., a cor- Application March 18, 1940, Serial No. 324,599

25 Claims.

tain the desired length of operating stroke by the use of additional mechanical means designed to multiply the comparatively small amplitude of movement transmitted by the armature so that the resultant movement will be suflicient for operating the cutter. Also, in such prior vibratory motors the current consumption was comparatively high. The prior art has not disclosed, so far as I am aware, a vibratory motor suitable for embodiment in a dry shaver of the type contemplated'foruse in the present invention; nor has the prior art disclosed an available solution of the problem of providing a motor of this type which will deliver an adequate, controlled, power stroke with minimum current consumption and no objectionable noise or vibration, and which is so constructedas to permit of economical production manufacture.

One of the'obiects of my invention is, therefore, to provide an improved vibratory electromagnetic motor for general application, but particularly adapted for the problems in small hand tools and implements such as dry shavers.

Another object is to provide a motor of this type which will transmit a comparatively long stroke with small power consumption without objectionable noise or vibration and which will have comparatively long life.

Another object of my invention is to provide an improved method of manufacturing a vibratory eletromagnetic motor of the character described.

Another object of my invention is to provide an electric dry shaver having improved means for operating the movable cutter.

Other objects deal with improved features of construction both in reference to the motor and the shaver and the combination thereof I In furtherance of these general objects I have provided certain improvements, the nature of which is disclosed in the following description and drawings and set forth more'particularly in the appended claims.

' I Referring to the drawings:

' Figure '1 is a side elevation of an electricdry shaver embodying my invention with the front cover removed, showing, the shaver approximately twice actual size;

Fig. 2 is a longitudinal section through the shaver taken substantially on the section line 2-2 of Fig. 1;

Fig. 3 is a longitudinal sectional view taken substantially on the section line 3-3 of Fig. 1 with the cutting head assembly in elevation;

Fig. 4. is an enlarged sectional view taken substantially on the section line 4-4 of Fig. 1 showing the cutter moved to one end of the stroke;

Figs. 5 and 6 are enlarged cross-sections taken substantially on the section lines 5-5 and 6-6, respectively, of Fig. 1;

Figs. 7 and 8 are face and side views, respectively, of the driver armature and vibratory spring removed from the motor, shown on'a reduced scale; a

Figs. 9 and 10 are face and side views, respectively, of the idler armature removed from the motor, shown on a reduced scale;

Fig. 11 is a longitudinal sectional view through the coil and field assembly removed from the motor;

Fig. 12 is a section l2l2 of Fig. 11; and

Fig. 13 is a cross-sectional view tially on the section line l3-l3 of Fig. l.

Before entering into a detailed description of the structure shol in the drawin s, it should be observed that my invention relates generally to the art of electric dry shavers of the type adapted to be operated by a vibratory, electromagnetic motor, and specifically to problems involvingmotor construction and function peculiar to the operation of a dry shaver. However, my invention in its broader aspects is not limited to a vibratory motor for operatinga dry shaver, but is adapted for other applications particularly in taken on the section line small hand tools where a comparatively long working stroke or armature motion is desired. My invention also contemplates certain improvements in respect to the motor housing and to certain features, co-acting between the housing and the sha ing head structure. I

In the example here shown for purpose of illustration the vibratory motor is carried in a housing which carries a shaver head at one end and also constitutes'a handle of such size that it may be held in the palm of the hand for manipulating the shaver head. The housing comprises a base part l5 and a cover It, preferably of molded Bakelite or any suitable composition material. The cover is detachably secured to the base part taken substan ,shown in Figs. 3 and there are wardly, in which case the cam at instance semi-circular,

the vibratory motor to of the housing by screws l1 and I8, Fig. 3. As two screws I! each of which is threaded into an adaptor screw [9 which in turn is threaded into a metal insert 2| in the base part I 5. As shown in Fig. 5 the head of each adaptor screw I9 is pulled down tight against the wing extensions 22 formed integral with a die cast frame unit designated generally by 23 constituting the main frame structure upon which the co-acting shaver parts are mounted or assembled, the whole constituting a shaver head assembly which will be presently more fully described. The third screw I8 is threaded into a similar but larger adaptor screw 24 which in turn is threaded into a metal insert 25 in the base part l5, as best shown in Fig. 3..

' The head of this adaptor screw 24 is pulled tight 26 of a bracket designated against the portion which the vibratory motor is generally by 21 upon mounted. This bracket in turn is fixedly mounted on the base part not only of the adaptor screw 24 but by two additional screws 28 which clamp against depending.

l5 of the housing by means extensions 29 integral with the lower end 'of bracket 21. A

The shaver shown operates on the principle covered in Patent No. 2,081,694 granted May 25, 1937, to John Bruecker and includes features claimed in the application of John Bruecker, Serial Number 178,221, filed-December 6, 1937. This shaver is known under the trade-marks Sunbeam Shavemaster. Briefly, the shaver head assembly comprises a removable comb 3|, a cutter hairs which protrude blade 32, a blade holder 33 and the frame unit 23 above mentioned, together with spring clamps 34 for securing the comb in position on the head. As best shown in Figs. 1 and 4, each spring clamp 34 is fixed at its lower end to a side wall 'of the frame unit 23 as by means of riveting and interfitting with the bottom edge of the side wall.

Each spring 34 normally tends to assume a retracted position, as shown at the left in Fig. 4,,in which position the detent at the outer end of the spring is ,withdrawn ing recess in the comb structure. spring detent in the locking position I employ a clamping member pivoted on an extension of the housing structure and having a cam surface at its inner end either of two positions; the locked position shown at the right'in Fig. 4 and the released position shown at the left. Each clamping member 30' is preferably of suflicient width to straddle the spring 34 and conceal it from view when in the locked position. To unlock and release the comb the operator may engage his fingernail the outer edge of each member 30 to swing it outthe inner end of such member releases the spring 34 which retracts to the released position. The comb 3| has an extremely thin skin-engaging portion, in this provided with small hairreceiving perforations. The blade holder 33 is mounted on trunnions journaled in the end portions of thedie cast frame 23. The blade holder is adapted to be rapidly oscillated by means of 'move the cutter back and forthacross the underside of the perforated portion of the comb, in this instance through an arc of approximately sixty degrees. As a c onsequence of this rapid oscillation, the cutter blade is urged outwardly by centrifugal force into intimate shearing engagement with the inner side of co-acting with the spring to be.

or any small object beneath tions of U-shape, having a ating conditions.

. understood by those skilled in through the small openings My invention provides for oscillating the cutter blade in a stroke of the desired length by novel means capable of economic production and adapted for satisfactorily performing this work. The stroke here desired is several times longer than in other types of shavers and the working load is greater. Furthermore, it is desired to control the length of the stroke to a fine degree of accuracy to obtain predetermined co-action between the cutter and the hair-receiving perforations. Also, voltage and frequency variations have an important bearing on the problems. The suppression of vibration and noise is a further problem in the present invention.

My invention will be better understood by considering in a preliminary way certain of the oper- It is desired to operate the motor with the commonly used alternating current furnished by electric, power companies. The current characteristics differ in some localities but generally the current supplied by the electric power companies is cycle alternating current of 110 to 120 volts. While it is the general practice of these power companies to maintain the rated cycle at such uniform frequency that ,electric clocks may be operated there are, nevertheless, at times some slight variations in frequency' within plus and minus one-half cycle and vari- 10 volts. With the,

Since there are two peaksduringeach cycle, the cutter blade makes 72Q0 complete oscillations each minute using 60 cycle alternating voltage as will be this art as the invention becomes better understood.

Referring now to the motor constructions, it

generally by 35 central portion 36 which carries the field winding and spaced parally by 46 is wound allel portions 31 and 38 which constitute opposed pole pieces. The laminations are clamped together by rivets '39. The central group of laminations shown by the dimension 4| in Fig. 6 are extended downwardly at 42 beyond the lower end 44 integral with the bracket 21. These bracket parts 44 are rigidlyclamped to the interposed laminations'42 by suitable means such as rivets The field coil designated generupon a spool 41 of insulated In commercial practice I prefer to material.

the comb and by this action serves to cut oil the'. 75 mold the spool 41 around the field structure. The

alternating current weight member,

endsuandlloithecoilaresultablyeonnecie wires II which in turn are connected to a suitable busbai' having terminal posts I! adapted for connection with a suitable current supply plug 04.

My invention contemplates the provision of a vibratory motor having certain structural and functional characteristics which enable the obtaining of a comparatively long motion transmitting stroke, comparatively small and compact tion of vibration and noise. These objectives are attained in part struction which includes counteracting armatures or a driving armature and a counteracting together with vibratory spring members of novel construction and function which carry the armatures or the driving armature and the weight member. My invention provides for so constructing these vibratory spring members that either one or both serves to carry an armature. In the embodiment shown in the drawings one spring member carries a driving armature and the other an idling armature in parallel in the magnetic circuit. However, as explained hereinafter. the idler member need not function as an armature. I also provide that the driving armature shall have less reluctance than the idler armature. I further provide that the spring of the driving member shall be tuned substantially higher than the spring of the idler member. The Purpose of the foregoing is to maintain the field mass as well as the housing field is fixed, practically free noise, and also to control members and armature to a close degree. In the present embodiment, a an idler armature 50 are shaped for co-action between the pole pieces by movement toward and from each other in the space between the pole pieces under attraction of the magnetic flux flowpath shown in Fig. 11 and dividing into parallel paths as each will be later with reference to Fig. 6. Each armature is mounted on the outer end of a vibratory spring which in turn is mounted at its opposite end on the non-magnetic bracket 21. The driver armature shown in Figs. '1 and 8 comprises a flat spring 51 having elongated sides I joined by inner and outer end portions 59 and H respectively, the armature laminations before mentioned. a number of laminations 02 of non-magnetic material such as brass for providing additional controlled mass, and a drive transmitting arm 01 terminating in a cylindrical shaped end N, these parts being fixedly clamped together by rivets 05. The idler assembly comprises a spring I! of shape similar to the spring 51 but preferably of different vibration characteristics as will be presently described. the armature laminations 80 before mentioned, a number of nonmagnetic lamination: 01 for additional controlled mass, and rivets 00 fixedly clamping the parts together. As shown in Figs. 2 and 3 the springs 51 and 00 are clamped at their lower ends to opposite sides 00 of bracket 21, which sides are disposed in planes convergin downwardly toward the center line of the motor. An angular clamping plate II is applied to the outer side of each spring for clamping the springs to the bracket 21, suitable means such as rivets 12 being empresslire. As best shown in Figs. 1, '7, and 9, there are three driving armature 55 and by the novel motor conmally flat springs are disposed in planes conver ing downwardly toward the center line of the motor with the upper ends. spaced apart suiilof the driver and idler armatures or weight as the case may be, an poximity at the mounting end and to bring the center of gyration of the armature closer to the center line of the motor. The springs are preferably punched to shape from flat, blue, spring steel, and in this embodiment they are of a Rockwell hardness of approximate- 1y 49-50 scale. As above stated, the springs are tuned to'diilerent frequencies, the driving member being tuned from 1,000 to 2,000 complete vibrations per minute higher than the idler member. In actual practice in the embodiment here illustrated: the driving member is tuned to a natural frequency of from 9,100 to 9,400 and the idler member from 7,300 to 7,600. These natural frequencies are, of course, higher than the line frequency which for cycles alternating current is 1200. It may also be stated that the spring member of the driver has a spring constant of a predetermined or controlled degree larger than the spring constant of the idler spring member. In actual practice, I- obtain these structural and functional characteristics of the spring members by precision grinding them to the desired fractional dimensions wherein the range of diflerence in thickness between the driving and idler spring members is from 5 to 15 per cent. Inactual commercial roduction of this motor for the purp fle here shown, the limits I have used for the diflerence in thickness between the driving spring member and the idler spring member is from 1.8 per cent to l3.3 per cent.

Referring now to the operation, it will be observed that sincethe driver armature is connected to the shaver head for oscillating the cutter, massisaddedtothe armature andthis has a tendency to lower the natural frequency of the driving system. The vibration energy of thedriver action in vibration and noise would be very objectionabie. This is remedied by myinvention which provides an additional controlled mass for counteracting the reaction energy from the driver armature, thereby relieving the field mass and the housing from objectionable vibration. This is provided by the idler spring and the controlled weight or mass of the idler member. There are two distinct ways .in which energy can be transmitted to this idler member. One is by energy transmitted from the field mass through the spring support directly to the idler member; the other is by energy transferred from the held, that is. by magnetic force to the idler armature when an armature is applied to the idler member. My invention maybe practiced by utilizing only the energy directly transmitted to the idler member as through the spring support to sustain the desired counteracting vibrations, although in this form small vibration of the spring support and housing takes place. when the idler member is utilized as an for space saving armature the additional ship to the energy transmitted from the driver. adap 4 2,299,962 energy more effectively serves to sustain vibrapieces, a drive armature and an idler armature tion of the idler member in controlled relationin spayed relation between said pole pieces to be drawn toward each other by the As stated above, both the driver and idler vibraflow or the magnetic flux between the pole plitude of the vibratory members could become the ends of the springs remote from the armastationary part and thus cause noise. and probaopenings. ble damage, or if there was suflicient clearance 2. In a vibratory electromagnetic motor, a fleld stated, the driver armature is tuned substantially wound about said central portion and projecting higher than the idler member. One reason for laterally beyond opposite sides thereof, an armathis is to counteract the mass which is added by ture for co-action with the pole pieces, a weight connection to the shaver head, which tends to havinga counteraction function in relation to the mass and decreasing the spring constant of the with respect to the other. 7 idler member the two phase angles will be 3. In a vibratory electromagnetic motor, a field brought closer together. By adding only sufllcore and a coil in a cross formation transversely c ent magnetic material to the idler member so of the longitudinal axis of the motor, a motor the working stroke is controlled by tuning the 40 aii'orded between the inner wall of the casing and line voltage from the minimum to the maximum and field assembly having a given centerline and the idler armature respectively. However, as on a non-magnetic bracket which is interposed above stated, it is not essential to use the idler between the vibratory springs at their closer member as an armature, but instead this maybe spaced end and has converging faces against used to provide an additional controlling means which the springs are seated, headed fastening fications as fall within the true spirit and scope formed at the opposite end to provide opposed I claim: central portion, a supporting member to which 1. A vibratory electromagnetic m t having the field core is mounted at its end opposite from an inductance coil, field laminations passing the pole pieces, a pa f Vibratory members a through the coil and terminating in opposed pole of s bs a a y flat p g material ped to opposite transverse supportin member and portions in proximity to the pole pieces and with the longitudinal side portions straddling the field winding coil at opposite ends thereof, an armaturefixed to the outer transverse portion of one of the spring members and arranged to be attracted by the fiow of fiux between the pole pieces, and a weight mounted on the outer transverse portion of the other spring member in predetermined reaction relation to the armature carrying sprin member.-

6. A vibratory electromagnetic motor as set forth in claim 5, including a hollow housing in which the described motor parts are supported through the intermediary of the S p rting member, the supporting member being fixedly mounted to the hollow case at a point on the centerline of the motor located within the opening defined by the side and transverse portions of the spring members and further fixedly mounted to the casing at two points laterally spaced from said centerline and located beyond the mounted end of the spring members.

'7. In a vibratory electromagnetic motor a field core having opposed parallel portions joined at one end by a central supporting portion and formed at the opposite end to provide opposed pole pieces, a field magnet coil wound on said central portion, a supporting member to which the field core is mounted at its end opposite from the pole pieces, a pair of vibratory members each of substantially fiat spring material shaped to provide longitudinal side portions joined at oppostie ends by transverse portions, the transverse portions at one end being fixedly secured to the supporting member and arranged to position the opposite transverse portions in proximity to the pole pieces and with the longitudinal side portions straddling the field winding at opposite ends thereof, an armature fixed to the outer transverse portion of one of the spring members and arranged to be attracted by the how of flux between the pole pieces, and a predetermined weight mounted on the outer transverse portion of the other spring member, the spring members having predtermined vibration frequencies, that of the armature member being higher than the weight member.

8. A vibratory electromagnetic motor having a field core comprising laminations of U-shape having parallel arm portions joined by a central portion, a field magnet coil wound on said central portion, the parallel arms formed to provide opposed pole pieces, a supporting bracket to which the core is fixedly mounted at its end opposite from the pole pieces, a pair of fiat vibratory spring members fixedly mounted at one end to the supporting bracket at opposite sides thereof and each having a central opening through which the adjacent end portion of the field coil projects, the springs being mounted in relatively close relation one with respect to the other, a driver armature fixed to the outer end of one of the spring members and a weight fixed to the outer end of the other, said spring members positioning the driver armature and the weight in opposed relation between the pole pieces.

9. A vibratory electromagnetic motor having a field core comprising laminations of U-shape having parallel arm portions joined by a central portion, a field magnet coil wound on said central portion,

the parallel arms formed to pro- 78 a 9,999,969 5 provide longitudinal side pcrtiom joined-at oppovide opposed pole pieces, a supporting bracket to site endsby transverse the transvers whichthecoreisfixedlymounted at its end opportions at one end being fixedly secured to the posite from the pole pieces, a pair of vibratory spring members fixedly mounted at one endto the supporting bracket at opposite sides thereof, a driver armature fixed to the outer end of one or the spring members and an idler armature fixed to the outer end of the other, said spring members positioning the driver and idler armature in opposed relation between the pole pieces so as to be drawn toward each other by the magnetic fiux.

10. A vibratory electromagnetic motor having a field core comprising laminations of U-shape having parallel arm portions joined by a central portion, a field magnet coil wound on said central portion, the parallel arms formed to provide opposed pole pieces, a bracket or non-magnetic material to which the field core is fixedly secured at its end opposite from the pole pieces, and vibratory spring members fixed at one end to opposite sides of the bracket, each spring member having a central opening and arranged in relatively close proximity to the field core with the adjacent side portion of the coil winding extending through its central opening, one of said spring members having at its opposite end an armature arranged to be attracted between the pole pieces and the other spring member having a weight fixed to its free end in predetermined reaction relation to the armature member.

11. A vibratory electromagnetic motor having a field core comprising laminations of U-shape having parallel arm portions joined by a central portion, a field magnet coil wound on said central portion, the parallel arms formed to provide opposed pole pieces, means fixedly clamping the laminations together, a central group of the laminations being extended at said arm portions at the ends opposite from the pole pieces to provide supporting lugs, a bracket having bifurcated end portions to receive said supporting lugs, means fixedly clampin the bracket end portions to the lug portions, the bracket serving to support the core and winding, and vibratory spring members fixed at one end to opposite sides of the bracket, one of said members having at its opposite end an armature arranged tobe attracted between the pole pieces and the other member having a weight fixed to its free end in predetermined reaction relation to the armature member.

12. A vibratory electromagnetic motor comprising a housing member, field laminations shaped to provide spaced parallel portions joined by a central portion, and an inductance coil around the central portion, said parallel field portions extending beyond the coil and said extending portions providing opposed pole pieces, a portion of the field laminations extending from said central portion in a direction opposite from the portions providing pole pieces, a bracket of non-magnetic material shaped to receive and provide rigid support for the second mentioned lamination extensions, means fixedly connecting the last named lamination extensions to said bracket, vibratory spring members attached to opposite sides of said bracket and extending lengthwise of the field laminations substantially to the pole piece end thereof, an armature member fixed to the upper end of one of said spring members in a position for magnetic attraction between the pole pieces, a weight member fixed to the upper end of the other spring member in reaction relation to the armature member, the bracket being shaped to provide a bottom extension below the point or 'atattached thereto consti-' disposed i'or operation between said pole-pieces,

comprises spaced longitudinal side portions joined by a transverse end portion at the end remote from its fixed support, the armature and weight members being attached to said transverse end portions, the spaced side portions of ach spring member providing an opening and the spring members being arranged in relatively close proximity to the laminating field and with opposite side portions of the coil extending through said openings, the longitudinal side por tions of the spring members being fixed at their lower ends to the bracket, the bracket having an upward extension located between the spaced longitudinal side members, and means fixedly securing said upward extension to the housing member.

14. A vibratory electromagnetic motor as set forth in claim 12, including a head unit mounted on the housing member adjacent to the armature end of said unit of assembly, the head unit having an operating member oscillatable in a given arc, means on the armature member, coacting with said operating member to oscillate the same in said are by vibratory action, the coacting relation between said means and said operating member being determined by the relative position of the unit of assembly with respect to said head unit as determined by the mounting of said unit of assembly through said bracket.

15. A vibratory electromagnetic motor comprising a housing member, field laminations shaped to provide spaced pole pieces, an induct-' ance coil coacting with the field laminations and carried thereby, a bracket of non-magnetic material shaped to provide rigid support for the field laminations and coil, means fixedly connecting the field laminations to said bracket, vibratory spring members attached to opposite sides of said bracket weight members coacting with the pole pieces, said bracket and said parts attached thereto constituting a unit of assembly, means fixedly connecting said bracket to said housing member and provided with armature and having parallel arm portions joined by a and means individually ture comprising a fiat spring having spaced longitudinal side portions joined by transverse end portions, each attached at armature and mounted at the opposite end portion in fixed relation to the" field core at a point opening in each flat spring, the coil projecting beyond opposite sides ot the field' core, said extending through the central openings of the respective springs I 17. In a vibratory electromagnetic motor, a

U-shaped field structure, a field winding carried by the central portion of the field structure, the spaced portions oi the field structureforming opposing pole pieces, a non-magnetic bracket upon which the field structure is mounted at its endopposite from its pole pieces, an armature, and a vibratory spring comprising a fiat spring member having longitudinal side portions in-laterally spaced relation joined at their endsby transverse end portions, the spaced relation of the pole pieces. 1

18. A vibratory electromagnetic motor having a field core comprising laminations of U-shape central portion, a field magnet coil wound about said central portion, the parallel arms formed to provide opposed pole pieces, a supporting bracket to which the core is fixedly mounted at its end opposite from the pole pieces, a pair of vibratory spring members fixedly mounted at one end to the supporting bracket at 01', and an armature fixed each of the spring members, said spring members tion or the face of each pole to support said unit of assembly thereon, said housing member shaped to receive said unit of assembly 'without contact therewith except for the supporting contact with said bracket, 9, head unit mounted on the housing member adjacent to the armature end of said unit of assembly and having an operating member coacting with one of the vibratory spring members to be operated thereby, an adapter screw connecting the head to the housing member, an adapter screw included in said means connecting the unit of assembly to th housing member, a cover for the housing member, and screws threaded into said adapter screws for connecting the cover to the housing member.

16. A vibratory electromagnetic motor including an inductance coil, a field having a core por-- tion passing through the coil and spaced portions extending beyond the coil forming opposing pole pieces, a driver armature and an idler armature positioning the armatures in opposed relation between the pole pieces so as to be drawn toward each other by the magnetic flux, the central porpiece being cut away to provide spaced projecting pole pieces for concentrating the fiow of flux along separate planes, one for attracting each armature.

19. A vibratory electromagnetic motor having a field core of laminations shaped to provide spaced pole pieces joined by a central portion a centrated by the projecting pole pieces at the other side, and an armature for the projecting pole p1eces at each side of the field core mounted pieces toward the center of the core but restricted 1n such inward movement by attraction of supporting each armaone end portion 'to its providing a central said flux tending to move the armature outwardly.

20. A vibratory electromagnetic motor as set forth in claim 19, in which the laminations extend lengthwise of the field core and each armature is composed of a vibratory spring member having a'plurality of armature laminations attached thereto, said armature laminations being of a length corresponding substantially with the length of the projecting pole pieces and each set of said armature laminations being supported by its vibratory spring member for movement between its respective set of projecting pole pieces, one or said armatures having a work transmitting member, and the latter armature having a greater number of laminations than the other to provide less reluctance than said other armature.

21. A vibratory electromagnetic motor having a field core comprising laminations shaped to provide spaced pole pieces joined by a central portion, a field magnet coil around said central portion and projecting beyond opposite sides of the pole pieces, a support to which the laminated field is fixed at its end opposite from the pole pieces, a fiat vibratory spring member at each said opposite side of the pole pieces, each spring member being fixed at one end to said support and extending lengthwise of the laminations substantially coextensive with the length thereof, each spring member having spaced longitudinal side portions joined by a transverse end portion at the end remote from its fixed support, the spaced side portions of each spring member providing an opening and the spring members being arranged in relatively close proximity to the laminated field with the oppositely projecting portions of the coil extending through said openings, an armature element on the transverse end portion of one of the spring members coacting with the pole pieces, and a weight element of predetermined mass on the transverse end portion of the other spring element in predetermined counteracting relation to the armature element.

22. A vibratory electromagnetic motor as set forth in claim 21, in which the spring members in their normal idle position are in planes converging toward the support.

23. A vibratory electromagnetic motor as set forth in claim 21, including a drive transmitting member attached to the armature carrying spring member at the armature end thereof, and in which the armature carrying spring member is tuned to a frequency higher than the other spring member.

24. A vibratory electromagnetic motor having a support, an electromagnet mounted on the support, an armature member and an idler member, a fiat vibratory spring for each said member fixed at one end to the support and carrying its respective member in coacting relation with the electromagnet, the parts being constructed and arranged so that the armature member is vibrated in response to magnetic attraction of the electromagnet and the idler member is vibrated at least in part in response to reaction forces from said armature member vibration, each fiat spring member being ground substantially over its entire opposite flat side surfaces to a prede-. termined thickness to a high degree of precision to thereby provide in each member a predetermined vibration frequency, the armature member serving as a work transmitting member, and

the fiat spring of said armature member having a vibration frequency of a predetermined degree higher than the flat spring of said idler member efiected by said surface grinding.

25. A vibratory electromagnetic motor having field laminations shaped to provide spaced parallel portions joined by a central portion, an inductance coil around the central portion, said parallel field portions extending beyond the coil and said extended portions providing opposed pole pieces, a support to which the field laminations are mounted at the end thereof opposite from the pole pieces, fiat springs of substantially the same configuration each having a predetermined thickness difierent from the other to provide a predetermined vibration frequency, the flat springs being positioned at opposite sides of the field laminations substantially coextensive with the length thereof and each fixedly mounted at one end to said support at the lamination supporting end thereof, the opposite end of each spring being in coacting relation with the pole pieces at the adjacent side of the field laminations, and fiat laminated armature and weight members fixed in superimposed relation to the fiat sides of the spring members at the end thereof coacting with the pole pieces, said laminated members being substantially parallel with the flow of flux between the pole pieces and support-. ed by the respective flat springs so as to move between the pole pieces in a plane transverse to said flow of flux.

IVAR JEPBON. 

